[Defender Pro] Error instaling defender

When I activate defender PRO I get the following error
atal error: Uncaught Error: Call to undefined function Hammer\Base\sanitize_textarea_field() in /home/simone/domains/simonevandenhil.nl/public_html/wp-content/plugins/wp-defender/vendor/hammer/base/model.php:104 Stack trace: #0 /home/simone/domains/simonevandenhil.nl/public_html/wp-content/plugins/wp-defender/vendor/hammer/wp/settings.php(55): Hammer\Base\Model->doFilters() #1 /home/simone/domains/simonevandenhil.nl/public_html/wp-content/plugins/wp-defender/main-activator.php(308): Hammer\WP\Settings->save() #2 /home/simone/domains/simonevandenhil.nl/public_html/wp-content/plugins/wp-defender/wp-defender.php(299): WD_Main_Activator->activationHook() #3 /home/simone/domains/simonevandenhil.nl/public_html/wp-includes/plugin.php(524): wp_defender_activate(”:wink: #4 /home/simone/domains/simonevandenhil.nl/public_html/wp-admin/plugins.php(166): do_action(‘activate_wp-def…’:wink: #5 {main} thrown in /home/simone/domains/simonevandenhil.nl/public_html/wp-content/plugins/wp-defender/vendor/hammer/base/model.php on line 104